Michele R. Forman

Carotenoid content of fruits and vegetables: An evaluation of analytic data

The test of the association between dietary intake of specific carotenoids and disease incidence requires the availability of accurate and current food composition data for individual carotenoids. To generate a carotenoid database, an artificial intelligence system was developed to evaluate data for carotenoid content of food in five general categories, namely, number of samples, analytic method, sample handling, sampling plan, and analytic quality control. Within these categories, criteria have been created to rate analytic data for beta-carotene, alpha-carotene, lutein, lycopene, and beta-cryptoxanthin in fruits and vegetables. These carotenoids are also found in human blood. Following the evaluation of data, acceptable values for each carotenoid in the foods were combined to generate a database of 120 foods. The database includes the food description; median, minimum, and maximum values for the specific carotenoids in each food; the number of acceptable values and their references; and a confidence code, which is an indicator of the reliability of a specific carotenoid value for a food. The carotenoid database can be used to estimate the intake of specific carotenoids in order to examine the association between dietary carotenoids and disease incidence.

Breastfeeding and incidence of non-insulin-dependent diabetes mellitus in Pima Indians

BACKGROUND Early exposure to cows milk has been implicated in the occurrence of insulin-dependent diabetes mellitus but there is little information about infant-feeding practices and subsequent non-insulin-dependent diabetes mellitus (NIDDM). We examined the association between breastfeeding and NIDDM in a population with a high prevalence of this disorder, the Pima Indians. METHODS Glucose-tolerance status was obtained from a 75 g oral glucose-tolerance test. A standard questionnaire given to mothers was used to classify infant-feeding practices for the first 2 months of life into three groups; exclusively breastfed, some breastfeeding, or exclusively bottlefed. The association between the three infant-feeding groups and NIDDM was analysed by multiple logistic regression. FINDINGS Data were available for 720 Pima Indians aged between 10 and 39 years. 325 people who were exclusively bottlefed had significantly higher age-adjusted and sex-adjusted mean relative weights (146%) than 144 people who were exclusively breastfed (140%) or 251 people who had some breastfeeding (139%) (p = 0.019). People who were exclusively breastfed had significantly lower rates of NIDDM than those who were exclusively bottlefed in all age-groups (age 10-19, 0 of 56 vs 6 [3.6%] of 165; age 20-29, 5 [8.6%] of 58 vs 17 [14.7%] of 116]; age 30-39, 6 [20.0%] of 30 vs 13 [29.6%] of 44). The odds ratio for NIDDM in exclusively breastfed people, compared with those exclusively bottlefed, was 0.41 (95% CI 0.18-0.93) adjusted for age, sex, birthdate, parental diabetes, and birthweight. INTERPRETATION Exclusive breastfeeding for the first 2 months of life is associated with a significantly lower rate of NIDDM in Pima indians. The increase in prevalence of diabetes in some populations may be due to the concomitant decrease in breastfeeding.

The development and application of a carotenoid database for fruits, vegetables, and selected multicomponent foods

A carotenoid database for individual and multicomponent foods has been compiled that contains values for the five most common carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein) in 2,458 fruits, vegetables, and multicomponent foods containing fruits and vegetables. The database was used to estimate intakes of specific carotenoids for 19- to 50-year-old women (n = 1,102), using food consumption data obtained from dietary recalls in the US Department of Agriculture Continuing Survey of Food Intake by Individuals, 1986. The major contributors of alpha-carotene were carrots consumed as a single food or as an ingredient in multicomponent foods. Carrots, cantaloupe, and broccoli were the main sources of beta-carotene. Orange juices and blends, oranges, and tangerines were important contributors of beta-cryptoxanthin. Tomatoes and tomato products consumed as single foods or as ingredients in multicomponent foods provided most of the dietary lycopene. Contributors of lutein + zeaxanthin included collard, mustard, or turnip greens; spinach; and broccoli. The per capita consumption of total carotenoids (the sum of the five specific carotenoids) among these women was approximately 6 mg/day.

Effect of age, parity, and smoking on pregnancy outcome: A population-based study

OBJECTIVES The purpose of our study was to investigate the combined interactive effects of maternal age, parity, and smoking on pregnancy outcome. STUDY DESIGN This was a population-based Swedish study (n = 538,829). RESULTS Multiple logistic regression analysis showed that the smoking-related effect on the relative increase in the odds ratio of low birth weight and preterm delivery was significantly greater among multiparous patients than nulliparous; among multiparas, smoking increased the odds ratios for low birth weight and preterm delivery by 2.4 and 1.6; the corresponding relative increases in the odds ratios among nulliparas were 1.7 and 1.1, respectively. With advancing maternal age there was a smoking-related relative increase in the odds ratios for small-for-gestational-age births. Moreover, the age effect on the relative increase of low birth weight, preterm delivery, and small-for-gestational-age births was greater among nulliparas than multiparas. CONCLUSIONS Older smokers are at an especially high risk for small-for-gestational-age births, and parous smokers are at an especially high risk for low birth weight and preterm delivery.

Methylation variation at IGF2 differentially methylated regions and maternal folic acid use before and during pregnancy

Folic acid (FA) supplementation before and during pregnancy has been associated with decreased risk of neural tube defects although recent reports suggest it may also increase the risk of other chronic diseases. We evaluated exposure to maternal FA supplementation before and during pregnancy in relation to aberrant DNA methylation at two differentially methylated regions (DMRs) regulating Insulin-like Growth Factor 2 (IGF2) expression in infants. Aberrant methylation at these regions has been associated with IGF2 deregulation and increased susceptibility to several chronic diseases. Using a self-administered questionnaire, we assessed FA intake before and during pregnancy in 438 pregnant women. Pyrosequencing was used to measure methylation at two IGF2 DMRs in umbilical cord blood leukocytes. Mixed models were used to determine relationships between maternal FA supplementation before or during pregnancy and DNA methylation levels at birth. Average methylation at the H19 DMR was 61.2%. Compared to infants born to women reporting no FA intake before or during pregnancy, methylation levels at the H19 DMR decreased with increasing FA intake (2.8%, p=0.03, and 4.9%, p=0.04, for intake before and during pregnancy, respectively). This methylation decrease was most pronounced in male infants (p=0.01). Methylation alterations at the H19 DMR are likely an important mechanism by which FA risks and/or benefits are conferred in utero. Because stable methylation marks at DMRs regulating imprinted genes are acquired before gastrulation, they may serve as archives of early exposures with the potential to improve our understanding of developmental origins of adult disease.

Birthplace, Years of Residence in the United States, and Obesity Among Mexican-American Adults

Objective: To evaluate the association between birthplace (Mexico or U.S.) and obesity in men and women and to analyze the relationship between duration of U.S. residency and prevalence of obesity in Mexican immigrants.

Alcohol and body weight in United States adults.

Alcohol contributes more than 10 per cent of the total caloric intake of adult drinkers in the United States. However, the effect of alcohol on body weight has not been adequately studied in the general population. The association between weight and frequency of alcohol consumption was examined in two national cross-sectional surveys: the Second National Health and Nutrition Examination Survey (HANESII; n = 10,929) and the Behavioral Risk Factor Surveys (BRFS; n = 18,388). Linear multiple regression was used to estimate the independent effect of alcohol on weight, adjusting for smoking, age, diet practices, physical activity, race, education, and height. Among men, alcohol had only a slight effect on weight in either survey. However, among women, alcohol was associated with a substantial reduction in weight, which was as large as the effect of smoking. Compared with nondrinkers, women who consumed alcohol 7-13 times per week had the greatest reduction in weight: -3.6 kg (95% confidence limits [CL] = -5.6, -1.5 kg) in HANESII and -3.2 kg (95% CL = -4.9, -1.5 kg) in BRFS. Alcohol confounded the association between smoking and weight, and among women it accounted for nearly 45 per cent of the weight-lowering effect of smoking. Alcohol also diminished the weight-lowering effect of smoking in men, while in women the smoking effect was slightly enhanced. Further studies are needed to understand the causal mechanisms by which alcohol is associated with body weight.

Gestational vitamin D and the risk of multiple sclerosis in offspring.

Vitamin D may have a protective role in the etiology of multiple sclerosis (MS), but the effect of gestational vitamin D on adult onset MS has not been studied.

Maternal-recalled gestational weight gain, pre-pregnancy body mass index, and obesity in the daughter.

Objective:Emerging evidence suggests that exposures during fetal life affect adult metabolism. We assessed the relationship between recalled maternal pre-pregnancy body mass, gestational weight gain (GWG), and adiposity in the daughter.Design:Retrospective cohort study among mother–nurse daughter dyads in the Nurses’ Health Study II and the Nurses’ Mothers’ Cohort. Mothers of participants completed questionnaires regarding their nurse daughter in 2001.Participants:26,506 mother–nurse daughter dyads born between 1946 and 1964.Main outcome measures:Body mass index (BMI) of the nurse daughter at age 18 and in 2001.Results:At age 18, 561 (2.1%) daughters were obese (BMI>30), and in 2001, 5442 (22.0%) were obese. Adjusting for covariates, women whose mothers had a recalled pre-pregnancy BMI of 29 had a 6.1-fold increased risk of obesity at age 18 and a 3.4-fold risk of obesity in 2001, compared with women whose mothers had a pre-pregnancy BMI of 21. We found a U-shaped association between recalled GWG and offspring obesity. Compared with a maternal weight gain of 15–19 lb, GWG <10 lb was associated with a significant increase in obesity risk at age 18 (odds ratio (OR) 1.54, 95% confidence interval (CI) 1.02–2.34) and in 2001 (OR 1.27, 95% CI 1.05–1.53). High weight gain (40+lb) was also associated with obesity risk at age 18 (OR 1.81, 95% CI 1.22–2.69) and in 2001 (OR 1.74, 95% CI 1.48–2.04). These associations were stronger among mothers who were overweight before pregnancy (P for interaction=0.03), and they persisted with adjustment for birth weight.Conclusion:A high recalled pre-pregnancy BMI and extremes of recalled GWG are associated with an increased risk of adolescent and adult obesity in offspring, particularly when the mother is overweight. Pre-pregnancy weight and GWG may be modifiable fetal origins of overweight and obesity in women.

Maternal recall of infant feeding events is accurate.

STUDY OBJECTIVE--Retrospective infant feeding data are important to the study of child and adult health patterns. The accuracy of maternal recall of past infant feeding events was examined and specifically the infants age when breast feeding was stopped and formula feeding and solid foods were introduced. DESIGN AND SETTING--The sample consisted of Bedouin Arab women (n = 318) living in the Negev in Israel who were a part of a larger cohort participating in a prospective study of infant health and who were delivered of their infants between July 1 and December 15, 1981. Data from interviews conducted 12 and 18 months postpartum were compared to the standard data collected six months postpartum. MAIN RESULTS--As length of recall increased there was a small increase in the mean difference, and its standard deviation, between the standard and recalled age when breast feeding was stopped and formula feeding and solid foods were started. Recall on formula feeding was less accurate than recall on solid foods and breast feeding. In particular, among those 61% reporting formula use at the six month interview, 51% did not recall introducing formula when interviewed at 18 months. The odds ratio (95% CI) of stunting versus normal length for age for formula fed versus breast fed infants based on recall data (OR = 2.07; 95% CI 0.82-5.22) differed only slightly from those based on the standard data (OR = 2.21; 95% CI 0.77-6.37). The accuracy of a mothers recall varied with her childs nutritional status at the time of the interview, but not with other sociodemographic, infant, or interviewer characteristics. CONCLUSIONS--Retrospective infant feeding data based on maternal recall of events up to 18 months in the past can be used with confidence in epidemiological studies. However, data on formula feeding may not be as accurate as data on breast feeding and solid food feeding, and accuracy may decrease as length of recall increases.